Generally, motors, e.g. TEFC type motors are primarily employed in the chemical, petroleum, mining, pulp and paper and lumber industries. As such, the motors are required to run continuously for long periods of time in an environment deluged with moisture, chemicals, dirt, dust and other forms of debris. Clearly, such conditions have a dramatic effect on motor life, which eventually leads to costly repair, higher energy costs and concomitant productivity disruption.
The prior art has attempted to circumvent the problem by producing various forms of covers and enclosures, typical of which is U.S. Pat. No. 4,886,320.
The patentee discloses a fan assembly providing an enclosure for the fan or impeller to facilitate more efficient running of the motor. This reference does not teach a motor for use under the adverse operating conditions as set forth herein and accordingly, does not provide a shield for the motor housing or fan housing adapted to substantially prevent passage of debris therethrough.
Further, U.S. Pat. No. 2,726,343, provides a ventilated dynamoelectric motor in which end brackets, associated with the frame, include vents. Such a structure does not alleviate the problems addressed with the present invention since such ventilation permits fluid and particulate matter to enter the motor; this eventually leads to possible damage to the windings, bearings etc. of the motor. In addition, to the aforementioned, the periphery of the frame lacks a shell to prevent the accretion of material thereon.
U.S. Pat. No. 5,006,742 discloses a splash-proof cover for an electric motor providing sockets to permit connection with a power supply. This reference, although providing a splash cover, does not provide a fan enclosure and housing shield for substantially reducing exposure of fluid and particulate material to the fan and housing.
Additional prior art generally within the field of the present invention includes U.S. Pat. Nos. 4,631,433, 3,719,843, 4,945,270 and 4,931,681.